Piston-ring



E. O. BALLMAN.

PISTON RING.

APPLICATION FILED APR..2I, 1915.

1,369,075, Patented Feb. 22, 1921.

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PATENT orncs.

nnwni c. Barnum, orix'mxwoon, urssounr.

macaw To all whom concern: 7

Be it known that I, EDWIN. C. BALLMAN,

a citizen of theUnited States, and. residing at Kirkwood, in the county of St. Louis and Stateiof-Missouri, have invented a certain new andnseful Improvement in Piston'-.

ings, of whichthe following is a specifica- Thisiinvention relates to packing rin 1 and more particularly, to packing rings or pistons.

.In all types'of packing rings as heretoforeconstructed there is always a small leakage course, separate, age at the 'oint.

through the slit or break in the ring;

f t c This is on account of the construction 0 ring. In the process of making such a ring as here'- tofore practised, a ring is first turned to a slight the cylinder, then slotted, then clamped on a mandrel, so that the slot closes, and turned and ground down to the inside dlameter of the cylinder. In the complete ring, the length is, however, that of the inside circumference of the cylinder, and, therefore, 1f all parts are to exact dimensions, the ends of the ring will come together. The ends will, however, just cometogether only for the smallest diameter of the cylinder, and when'the cylinder is cold. For variations inthe cylinder diameter, however, and when the cylinde is hot, the ends will, of

thereby causing the leak- One of t e objects of this invention, there-. fore,is to provide a packing which is tight both axially and circumferentially.

Another. objectis to rovide a ring, the

ends ofiwhich are held 111 ielding en age.-

ment, irrespective of the 'ameter an the condition of the cylinder.. Further objects willa'ppea'r from the detail description taken in connection -,.with. the

I shown. in

accompanying drawing, in which:

Figure lis an endfvlew of, a packing ring embodyin 1" this invention, the ring being ll lines in working position; Fig. 2 is a detail section through a cylinder showing the packing in position;

ig. 3 is a detail, showing another embodiment of this invent on;

Fig. 4 is a -view similarf toFi '1,show1ng still another embodiment of thisinvention; v I i r a description of its construction and method Fig. 5 is a side view of one of the rings; Fi 6- is a view similar to ,Flg. but showmg the packing illustrated in Figs. .4

Specification of Letters Patent.

y larger diameter than the inside of with the wall of the cyIinderQL-j' Patented Feb. 22, 1921.

Application filed April '21, 1915. Serial No. 22,918.

Fig. 7 is a view similar to Fig. 5, but showing still another embodiment of this invention; and

Fig. 8 is a detail side view of one of the shown in Fig. 7.

ririg's efe'rring to the accompanying drawing,

and, more particularly, to Figs. 1 and 2 10- designates a ring which decreases in thickness radially from, one side ,11 to the other side .12, the thickest part being at 11, and the thinnest part at 12. This ring is split to one side of the thinnest portion, and the ends 13and 14 are lapped toform a lap or scarf joint 15.

The a-p .lication -of such a packing is shown in ig. 2, in which 5 designates the cylinder, 6 the piston and 7 the groove in the piston adapted to receive the packing. In practice, two packing rings 10 are placed side by side in the groove, and so arranged that the joint in one ring will'come diametrically opposite to the joint in the other ring, the ringsbeing held together by a pin 16 in one ring-engaging an aperture in the other ring.

The rin is so, constructed that its diameter, w en complete, will be slightlythat side of the joint, the underlapping part is held in yielding engagement with the overlapping end by the inherent resiliency of the rin and by the fluid pressure. The

result is t at the "ends of the ring are always held in engagement to close the joint, and this engagement is closer. the greater'the pressure of the gas inside of the cylinder, and, therefore, back of the Moreover, the joint remains tight for 'a variation in thediameter. Since the contacting faces of the joints are 'ress'ing together, there can be no leakage iametrically, and axially the leakage is prevented by the en gagement of the rings with eafch other and This action of the ring will be clear'from of manufacture.- In the manufacture of piston rin' as, is well known to those skilled in t e art, the ring blank is turned to a diameter a fraction of an inch greater than the cylinder in which it is to housed; a piece is then cut out of the ring, the ring is then contracted so that the spaced ends meet, and in such a position is placed on a mandrel and turned down to the correct diameter, that is, to the diameter of the cylinder; this will produce a ring which has the requisite tension, as the ends will tend to spring apart.- Now in accordance with this invention, the same general procedure is followed. The ring blank is turned to adiameter greater than the diameter of the.

position shown in Fig. l; the ring is now turned down to the diameter slightly greater than the diameter of the cylinder. It now the ring is placed in a c linder of the correct diameter, for which t -e ring is designed, the ends will be in the position shown in full lines, Fig. 1, in which the underlapping end will ,be held out of contact with the cylinder wall for some distance, as shown, the cylinder wall being shown by the dotted line from a to This will hold the lapped ends in close and firm engagement when the ring is in use in the cylinder, as previously described. it will, of course, be understood that the conditions are exaggerated in Fig. 1, as it will be seen that a slight swinging movementot the ring sections ba toward the cylinder surface, will compensate for quite a gap between the lapped ends. The leaka e between the sections 01 -6, and the c linder wall, will, therefore, be 'viy sight; moreover, this leakage is entirely overcome by placing two ring sections in lq80* spaced relation, as shown clearly in .mi 2. i

Big. 8 shows another embodiment of this invention, in which a lapped joint is formed by an overlapping end 20 and an underlapping end 21. To increase the re siliency at the joint on the underla ping the embodiment shownin Fig. 1. The ring N blank is in thiscase also turned to a diameter somewhat greater than the diameter of the cylindertin Wh chthe ring is to be used ;1 a piece istlnen frat of the ring, the ends lapped and the kerf 22 formed. If now a ring is contracted to a diameter slightly greater than the cylinder in which the ring is to be used, the pressure of the overlapping end on the underlapping end, will tend to force the portion 21 of the underlapping end away from the portion immediately above the kerf. If now the ring is turned on a mandrel to the true diameter of the cylinder for which the ring. is designed, the lapped ends are maintained in firm sealing engagement, and this sealing engagement is maintained when the portion above the kerf is in engagement with the cylinder wall, since this portion can yield independently of the underlapping end, without throwing the underlapping end out of engagement with the overlapping end. In this case also the ends 21 and 20 are held in yieldin engagement'by the inherent elasticity o the ring, and also by the gas pressure inside of the cylinder and back of the ring. The joint may, in this case, be at the thinnest or weakest part of the ring, as shown in Fig. 3, but may be at one side, as shown in Fig. 1, and, in this case, also, two rings may be placed side by side breaking joints.

In the construction shown in Figs. 4, 5' and 6, two rings 25 are slipped over one another and lapped axiall so as to form overlapping ends 26 and 2 ln'this case, one

end 27 is slit as shown at 28 and apertured as shown at 29, so as to weaken this part of the ring, and, therefore, maintain a yielding engagement of the ends 26and 27. This is accomplished in the manufacture of the ring in a manner similar to that heretofore described with the embodiment shown in Figs. 1 and3. The ring blank is, of course, of a width slightly greater than it's ,final width. After the piece has been cutout of the blank, the lapped ends are formed, so that when they are brought together, they will be held in firm engagement; for in view of the fact that these ends are formed independently, their engaging surfaces can be so formed 'as to require a lateral springing of the'ring when they are brought together. When, therefore, the ring is afterward machined. to its true width, these ends will be maintained in firm engagement, for the engagement of the ring portion on the other side of the kerf from the portion 27, will not throw the-lapped ends out of engagement, as the tree portion can yield independently. In this case, one ring is slippedover the wther, so as to break joints, and each ring is provided with a pin 30 engaging the apermm 2"? the other ring. Instead of making the ringof a varying thickness radiallyfrom its center toward its ends, in order to provide for a uniform pressure on the cylinder wall, the thickness may be made varying axially, as shown in Figs.

7 and 8. In these figures the rings 35 are made on an oblique section, with the thickest part at 36 and the thinnest part at 37,

two of these rings being placed side by sideto form the complete packing, with the thinnest part of one ring opposite the thickest part of the other ring. The joint is, in this case, also made to one side of the thinnest section, the end 39 underlapping the end 38, so as to form a lap or scarf joint 40. The rings are pinned together by a pin 4:1. The action of this rin is substantially the same as that shown in igs. 1 and 2, and further description will, therefore, be unnecessary.

The advantageous features described in connection with Figs. 1 and 2 also apply to the other embodiments of this invention. It will be seen that, in accordance with this invention, a tight joint is formed, both axially and diametrically,irrespective of variations in the diameter of the cylinder, and irrespective of the conditions of the cylinder. This is brought about by causing the ends of the ring alwaysto bear against one another, instead of both bearing against the cylinder wall, and this is obtained by keeping one end out of engagement with the cylinder wall, and by weakening the underlapping section adjacent the joint. The resiliency of the ends is, therefore, increased. As the packing is self-adjustable, the parts do not have to fit snug in the groove of the piston, so that they willnot, therefore, be easily afi'ected by oil, etc.

It is obvious that various changes may be made in the details of the construction without departing from the spirit of this invention. It is, therefore, to be understood that this invention is 'not to be limited to the specific construction shown and described.

Having thus described the invention, what is claimed is:

1. A packing ring having lapped ends forming ajoint, the ring having its underlapping section weakest to one side of the joint and adapted to flex at its weakest point so as to maintain the underlapping end in continuous contact with the overlapping end at the'joint.

2. A packing ring having lapped ends, with one end lapping the other end to form a joint, a portion of the ring at one side of one lapping end being constructed for independent movement toward the opposed lapping portion, when the ring is in use.

3. A packing ring having lapped ends, with one end lapping the other end to form a joint, said ring having a ciicumferential kerf formed in one of its ends at one side of the joint, the portions of the ring at opposite sides of said kerf being independently yieldable.

4. A. packing ring having lapped ends forming a joint, the underlapping end havin a weakened section extending to one si e of the' joint and adapted to bear lightly on the cylinder wall, whereby said underlapping end may yield relatively to the overla ping end, when the ring 1s in use ,in a cy inder.

In testimony whereof I afiix my signature this 7th day of April, 1915.-

EDWIN c. BALLMAN. 

